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poisonous plants

Some algae can be harmful to humans. A few species produce toxins that may be concentrated in shellfish and finfish, which are thereby rendered unsafe or poisonous for human consumption. The dinoflagellates (class Dinophyceae) are the most notorious producers of toxins. Paralytic shellfish poisoning is caused by the neurotoxin saxitoxin or any of at least 12 related compounds, often produced by...